I have gone the DP route before on a 350z and the noise was horrible (not trying to hate) as well as the fact you can't pass inspection. Went to high flow cats and was so happy the raspy sound went away, and was able to pass inspection.

I have seen AR makes a high flow cat but it's like $1k which is a bit ridiculous considering i paid half that for the 350z and that required two pipes.

Am i missing something or is the rasp not there and switching them before inspection once a year not that much work?

my last car had a a high flow Random Technology cat on my CP-E downpipe. For me, i would never own a car without a high flow cat ...just do not like the smell of the exhaust without it and certainly the inspection issues and CEL lights that seem to come for some..I no i may be dissing 5hp or so with the cat but my BMW 135i with the JB4 has more power than i need so i have not put a cat on this car till after my warranty is over..just to much a pain in the ass for me to take it off,.....Check with CP-E they make some great exhaust parts and they warranty there cats for the life of your car as well as getting it through inspection....